Since we're on the topic of LF response in the modal region, what does anyone think is the premise behind the Kef Blade's four side firing woofers crossed at 350hz 12db/octave ? I'm trying to find an advantage but I can't other than if sufficient in extension may act similiar to Earls mult sub approach.
When you say well designed loudspeaker I trust this actually means one that inherently has low distortion anyway? As you'd consider one that has high distortion and a very basic motor to be poorly designed?
5th element
Yes, of course, one could use poor speakers in a poor design and get audible distortion, but there are plenty of options that would have inaudible nonlinear distortion such that using it as a metric for comparison would be pointless.
Floyd Toole thinks so little of nonlinear distortion that it is not even mentioned in his book. In a "good" speaker it is simply not an issue.
Yes, of course, one could use poor speakers in a poor design and get audible distortion, but there are plenty of options that would have inaudible nonlinear distortion such that using it as a metric for comparison would be pointless.
Floyd Toole thinks so little of nonlinear distortion that it is not even mentioned in his book. In a "good" speaker it is simply not an issue.
It would not act as multiple sources, just one. It would be monopole up to the crossover region - "controlled directivity"? Certainly not what I would do.
Back on topic, this is how Gravesen says it: SEAS-3-Way-Classic-mkII
"Having a small 3½-4" driver bridging the gap between bass and treble is a good idea. The MCA12RC is extremely broad-banded and makes crossover work easy. Obviously it costs a little more to do a 3-way, but small 3-4" drivers simply handle the 1-3 kHz range better than any 6-7-8" driver can do, and we don't have to deal with the too common ragged roll-off profile of larger drivers,"
This speaker is crossed at 700Hz and 2,8kHz (exceptionally low for him!). Unfortunately he does not show off-axis measurements.
"Having a small 3½-4" driver bridging the gap between bass and treble is a good idea. The MCA12RC is extremely broad-banded and makes crossover work easy. Obviously it costs a little more to do a 3-way, but small 3-4" drivers simply handle the 1-3 kHz range better than any 6-7-8" driver can do, and we don't have to deal with the too common ragged roll-off profile of larger drivers,"
This speaker is crossed at 700Hz and 2,8kHz (exceptionally low for him!). Unfortunately he does not show off-axis measurements.
IMO, the Blade is all about making a visually striking speaker that's bigger than it looks to grab people's attention and showcase their concentric driver technology. They're way too close to each other to randomize room modes.
That's not an insult - KEF's concentrics are outstanding and the Blade looks cool. I've not heard the speaker but I'd be surprised if it wasn't very very good. It also makes me curious how high one can take side-firing woofers, because that's a great way to reduce apparent speaker footprint if one is targeting a wider pattern anyway.
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Agreed on all counts. What i truly like about the Blade is the creative use of available baffles space but still retain a slim design. The depth of the enclosure is not as easily perceived and in most cases, the user would have the available depth but not usually a wide baffle speaker. Clever.
No what i am referring to is intermodulation distortion where at least one of the IMD excitation frequencies lies within that range.
If you crossover at say 2Khz you drastically lower IMD produced by the woofer between frequencies >2KHz and everything else that the woofer is playing, and IMD from the tweeter from <2KHz and everything else the tweeter is playing.
Crossing most woofer higher than 4KHz also greatly increases your chances of IMD products landing on cone resonances. If you cross at 2KHz and you have cone breakup >4KHz it's impossible for that to happen. Most tweeters would also not be happy being crossed below 1KHz.
Building a 2-way and avoiding crossing over within the 1-4KHz range that is of interest to this thread would therefore seem like a bad idea if lowering IMD products produced from 1-4KHz signals was of importance ...
Show us the evidence that nonlinear distortion in a well designed loudspeaker isn't audible then.
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It depends on how you plan to reproduce signals 1khz and up.....midrange dome, dome tweeter mids ( SEAS, Morel, Ciare, Audax)multiple identical devices such as a vertical array or Bessel alignment, compression driver and waveguide or some of the new air motion devices like the Beyma TPL 150 or Aurum Cantus.
If we look closely at the problem, there's now thankfully quite a few ways to skin this cat.😉
mayhem13 I'd like to take this point you've made a spin it around a little ... to ask how you plan to reproduce signals below 1khz?
It seems to me that the hand off from woofers to mid/tweeters gets a bit dicey as the frequencies rise. The typical "fullness" that a good sized woofer adds to voices and instruments at the fundamentals ... good sized woofer meaning one that can reproduce LF content with some authority 12-15"... isn't something that is welcome around 1khz xo point .. at least to my ears.
This statement, in my mind, is mostly an attempt to redefine the threshold so as to use it to classify 'good' speakers. I can take any bass driver that Gedlee might choose and create highly audible nonlinear Doppler distortion with it.
That is simply not the point. I could do that too. The point is that the threshold for speakers is quite high since speakers are all low order non-linearity. It is quite easy to keep the excursions low enough that at any reasonable listening level the nonlinearities are below threshold.
If you think otherwise then you need to prove your case since those of use who have studied this problem for decades have all concluded the same thing.
If you think otherwise then you need to prove your case since those of use who have studied this problem for decades have all concluded the same thing.
.....but a pair of paper coned well made 8" woofers should sound excellent to your ears. Considering a vertical pair of such with the bottom woofer handling BSC and rolling off sooner higher in frequency eliminating vertical lobing as in many common .5 crossover topologies. As with the HF devices, there's a few 8's from Scanspeak, SEAS, Usher, Peerless, and Silver Flute that can do it quite well. On a budget, the Silver a Flute being an excellent choice!
The ability of a 12 or 15 driver to reach higher frequencies in a controlled fashion is highly specific to each individual design. A few can do it, most cannot.
Everything's a compromise Earl. Your approach with large format woofers to meet the needs of directivity at the crossover point exposes the listener to SQ issues not found in smaller format drivers......which in tern don't have the dynamic capabilities of their larger cousins. The more this gets examined, the more 'correct' line arrays appear. Yes, at a time as you put it the line array was not a practical approach. With today's smaller format driver capabilities, I'm convinced this is no longer true.
Mind if I ask you you're opinion on two 6-7" midwoofers side by side below an OS waveguide?
Mind if I ask you you're opinion on two 6-7" midwoofers side by side below an OS waveguide?
There are always compromises, but not all compromises are equal.
How so? I know this is the prevailing view, but I don't hold it.
I wouldn't do it. The directivities won't match. And I'd much rather have the dynamics of the larger driver as well.
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